Tartessol,a new diterpene fromSideritis grandiflora Salzm

Résumé Un nouveau diterpène tartessol (1) a été isolé de laSideritis grandiflora Salzm. (Labiées) est sa structure est proposée comme étantent-14-acétoxy-15-beyèren-18-ol.

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Part XVIII in the series Studies on diterpenes from genusSideritis. For Part XVII seeT. G. de Quesada, B. Rodríguez andS. Valverde,Phytochemistry, in press.

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The authors thank Dr.J. Borja, Botany Department, Faculty of Pharmacy, Madrid, for the collection and botanical classification of the plant material and Dr.Juana Bellanato, Institute of Optics, C.S.I.C., Madrid, for the high resolution IR spectra.     

Marine antitumor agents: 14-deoxycrassin and pseudoplexaurol,new cembranoid diterpenes from the Caribbean gorgonianPseudoplexaura porosa

Two new cytotoxic antitumor diterpenoids of the cembrane class, named 14-deoxycrassin (3) and pseudoplexaurol (4), have been isolated from the Caribbean gorgonian octocoralPseudoplexaura porosa. The structure of lactone3, possessing the infrequently encountered -methylene--lactone ring, has been established from spectral and chemical data and that of alcohol4 has been established from spectral data.     

Acyclic diterpenes containing 3 enol acetate groups from the green algaChlorodesmis fastigiata

Summary 2 new diterpenes, chlorodesmin (4) and dihydrochlorodesmin (5), each containing 3 enol acetate groups, have been isolated from Great Barrier Reef collections of the green algaChlorodesmis fastigiata (Chlorophyta, Caulerpales). Didehydrotrifarin (3) was also characterized.     

The structures of laurelliptine,a new aporphine alkaloid,and thalicmidine

Zusammenfassung Dem neuen ausBeilschmiedia elliptica isolierten Alkaloid Laurelliptin wurde die Struktur 1,9-Dimethoxy-2,10-dihydroxy-noraporphin (III) zugeschrieben. Die früher (vonShamma) vorgeschlagene Struktur für Thalicmidin (Ig) wurde bestätigt.     

Na-demethyl-purpeline and Na-demethyl-dihydropurpeline,new alkaloids fromRauwolfia cumminsii stapf

Summary N_a-demethyl-purpeline and N_a-demethyl-dihydropurpeline, new indole alkaloids, were isolated from the stem bark of Rauwolfia cumminsii Stapf. Dihydroindole alkaloids have not previously been reported as occurring in this species.     

Reticulol,a new metabolic isocoumarin

Zusammenfassung Die Struktur des ausStreptomyces rubreticulae isolierten neuen Isocumarins, Reticulol, ist als 3-Methyl-6,8-dihydroxy-7-methoxyisocumarin ermittelt worden.     

Baluchistine,a new bisbenzylisoquinoline alkaloid

Summary The new phenolic bisbenzylisoquinoline alkaloid (+)-baluchistine, found inBerberis baluchistanica Ahrendt (Berberidaceae), has been assigned structure1. O-Methylation using ethereal diazomethane yields (+)-obaberine (2). Baluchistine is the 1 alkaloid of the oxyacanthine-berbamine group to incroporate a free phenolic function at C-6.this project was supported by NIH research grant CA-11450, awarded by the National Cancer Institute, PHS/DHEW.     

5-Azacytidine,a new,highly effective cancerostatic

Zusammenfassung Die hohe bakteriostatische und cancerostatische Wirkung eines neuen Antimetaboliten, 5-Azacytidin, wird beschrieben.     

o-N-diisopropylaminoethoxy-butyrophenone,a new local anaesthetic drug

Riassunto Da una serie di-fenossietilamine acilate è stata selezionata una nuova sostanza e cioè l'o-N-diisopropylaminoetossibutirrofenone, che possiede elevate proprietà anestetiche locali di superficie, per infiltrazione e tronculari. Si sono comparate le attività anestetiche e la tossicità del nuovo composto con quelle della cocaina e della procaina.     

Deoxyribozymes: new activities and new applications

DNA in its single-stranded form has the ability to fold into complex three-dimensional structures that serve as highly specific receptors or catalysts. Only protein enzymes and ribozymes are known to be responsible for biological catalysis, but deoxyribozymes with kinetic parameters that rival ribozymes can be created in the laboratory. Some of these engineered DNA catalysts are showing surprising potential as therapeutic agents, which makes them biologically relevant if not biologically derived. If DNA's natural role is strictly genomic, how significant is its innate catalytic prowess? New examples of engineered deoxyribozymes serve as empirical examples of the potential for catalysis by DNA. These results indicate that the true catalytic power of DNA is limited by discovery and not by chemistry.